U.S. patent application number 12/578513 was filed with the patent office on 2010-02-04 for multi-port memory device having self-refresh mode.
Invention is credited to Chang-Ho DO, Jae-Hyuk Im.
Application Number | 20100027364 12/578513 |
Document ID | / |
Family ID | 37893705 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100027364 |
Kind Code |
A1 |
Im; Jae-Hyuk ; et
al. |
February 4, 2010 |
MULTI-PORT MEMORY DEVICE HAVING SELF-REFRESH MODE
Abstract
The multi-port memory device includes a mode input/output
controller for receiving a flag signal and generating a
self-refresh entry signal and a self-refresh escape signal, a
refresh interval signal generator for providing a self-refresh
interval signal notifying a self-refresh interval in response to
the self-refresh entry signal and the self-refresh escape signal, a
refresh cycle signal generator for periodically generating a
cycle-pulse signal during an activation of the self-refresh
interval signal, an internal refresh signal generator for producing
an internal refresh signal in response to the self-refresh entry
signal and the cycle-pulse signal, and an internal address counter
for generating an internal address in response to the internal
refresh signal.
Inventors: |
Im; Jae-Hyuk; (Kyoungki-do,
KR) ; DO; Chang-Ho; (Kyoungki-do, KR) |
Correspondence
Address: |
BLAKELY SOKOLOFF TAYLOR & ZAFMAN LLP
1279 OAKMEAD PARKWAY
SUNNYVALE
CA
94085-4040
US
|
Family ID: |
37893705 |
Appl. No.: |
12/578513 |
Filed: |
October 13, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11540381 |
Sep 28, 2006 |
7619942 |
|
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12578513 |
|
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Current U.S.
Class: |
365/222 ;
365/189.05; 365/191; 365/230.05; 365/236 |
Current CPC
Class: |
G11C 11/40615 20130101;
G11C 8/16 20130101; G11C 2207/105 20130101; G11C 2211/4065
20130101; G11C 29/50 20130101; G11C 29/50016 20130101; G11C 11/406
20130101; G11C 11/40611 20130101; G11C 7/1075 20130101; G11C 11/401
20130101 |
Class at
Publication: |
365/222 ;
365/230.05; 365/236; 365/191; 365/189.05 |
International
Class: |
G11C 7/00 20060101
G11C007/00; G11C 8/16 20060101 G11C008/16; G11C 8/00 20060101
G11C008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2005 |
KR |
2005-0090904 |
May 31, 2006 |
KR |
2006-0049135 |
Claims
1. A multi-port memory device comprising: a test-flag signal
generator for providing a test-flag signal; a mode input/output
controller for receiving one of a flag signal and the test-flag
signal in response to a test signal and generating a self-refresh
entry signal and a self-refresh escape signal; a refresh interval
signal generator for providing a self-refresh interval signal
notifying a self-refresh interval in response to the self-refresh
entry signal and the self-refresh escape signal; a refresh cycle
signal generator for periodically generating a cycle-pulse signal
during an activation of the self-refresh interval signal; an
internal refresh signal generator for producing an internal refresh
signal in response to the self-refresh entry signal and the
cycle-pulse signal; and an internal address counter for generating
an internal address in response to the internal refresh signal.
2. The multi-port memory device as recited in claim 1, wherein the
test-flag signal generator is a pad to which the test-flag signal
is applied directly from outside.
3. The multi-port memory device as recited in claim 1, wherein the
test-flag signal generator includes: a decoder for decoding a
plurality of test codes; a signal generator for activating an
output signal in response to an output signal of the decoder; a
first latch for inverting and latching an output signal of the
signal generator; and a first delay circuit for delaying an output
signal of the first latch to provide the test-flag signal.
4. The multi-port memory device as recited in claim 3, wherein the
mode input/output controller includes: a selector for selectively
providing one of the flag signal and the test-flag signal in
response to the test signal; a self-refresh entry signal generator
for generating the self-refresh entry signal in response to an
output signal of the selector; and a self-refresh escape signal
generator for producing the self-refresh escape signal in response
to the output signal of the selector.
5. The multi-port memory device as recited in claim 4, wherein the
selector includes: a first transfer gate for transferring the flag
signal to the self-refresh entry signal generator and the
self-refresh escape signal generator in response to an inactivation
of the test signal; and a second transfer gate for providing the
test-flag signal to the self-refresh entry signal generator and the
self-refresh escape signal generator in response to an activation
of the test signal.
6. The multi-port memory device as recited in claim 5, wherein the
self-refresh entry signal generator includes: a first RS latch for
taking an output signal of the selector as a set signal and a first
feedback signal as a reset signal; a first inversion delay circuit
for delaying and inverting a positive output of the first RS latch
to provide the first feedback signal; a first NAND gate for
receiving and NAND-operating the positive output and the first
feedback signal; and a first inverter for inverting an output
signal of the first NAND gate to provide the self-refresh entry
signal.
7. The multi-port memory device as recited in claim 6, wherein the
self-refresh escape signal generator includes: a second inverter
for inverting an output signal of the selector; a second RS latch
for accepting an output signal of the second inverter as a set
signal and a second feedback signal as a reset signal; a second
inversion delay circuit for delaying and inverting a positive
output of the second RS latch to provide the second feedback
signal; a second NAND gate for receiving and NAND-operating the
positive output and the second feedback signal; and a delay circuit
for delaying an output signal of the second NAND gate to output the
self-refresh escape signal.
8. A multi-port memory device comprising: a test-flag signal
generator for providing a test-flag signal; a mode input/output
controller, in response to a test signal, for receiving one of a
flag signal and the test-flag signal and generating a self-refresh
entry signal and a self-refresh escape signal, both of which are
inactivated in response to an initialization signal; a refresh
interval signal generator for providing a self-refresh interval
signal notifying a self-refresh interval in response to the
self-refresh entry signal and the self-refresh escape signal; a
refresh cycle signal generator for periodically generating a
cycle-pulse signal during an activation of the self-refresh
interval signal; an internal refresh signal generator for producing
an internal refresh signal in response to the self-refresh entry
signal and the cycle-pulse signal; and an internal address counter
for generating an internal address in response to the internal
refresh signal.
9. The multi-port memory device as recited in claim 8, wherein the
test-flag signal generator is a pad to which the test-flag signal
is applied directly from outside.
10. The multi-port memory device as recited in claim 8, wherein the
test-flag signal generator includes: a decoder for decoding a
plurality of test codes; a signal generator for activating an
output signal in response to an output signal of the decoder; a
first latch for inverting and latching an output signal of the
signal generator; and a first delay circuit for delaying an output
signal of the first latch to provide the test-flag signal.
11. The multi-port memory device as recited in claim 10, wherein
the mode input/output controller includes: a selector for
selectively providing one of the flag signal and the test-flag
signal in response to the test signal; a self-refresh entry signal
generator for sensing an output signal of the selector and
generating the self-refresh entry signal which is inactivated upon
receipt of the initialization signal; and a self-refresh escape
signal generator for sensing the output signal of the selector and
producing the self-refresh escape signal which is inactivated upon
receipt of the initialization signal.
12. The multi-port memory device as recited in claim 11, wherein
the selector includes: a first transfer gate for transferring the
flag signal to the self-refresh entry signal generator and the
self-refresh escape signal generator in response to an inactivation
of the test signal; and a second transfer gate for providing the
test-flag signal to the self-refresh entry signal generator and the
self-refresh escape signal generator in response to an activation
of the test signal.
13. The multi-port memory device as recited in claim 12, wherein
the self-refresh entry signal generator includes: a first RS latch
for taking an output signal of the selector as a set signal and a
first feedback signal as a reset signal; a first inversion delay
circuit for delaying and inverting a positive output of the first
RS latch to provide the first feedback signal; a first NAND gate
for receiving and NAND-operating the positive output, the first
feedback signal and the initialization signal; and a first inverter
for inverting an output signal of the first NAND gate to provide
the self-refresh entry signal.
14. The multi-port memory device as recited in claim 13, wherein
the self-refresh escape signal generator includes: a second
inverter for inverting the flag signal; a second RS latch for
accepting an output signal of the second inverter as a set signal
and a second feedback signal as a reset signal; a second inversion
delay circuit for delaying and inverting a positive output of the
second RS latch to provide the second feedback signal; a second
NAND gate for receiving and NAND-operating the positive output, the
second feedback signal and the initialization signal; and a delay
circuit for delaying an output signal of the second NAND gate to
output the self-refresh escape signal.
15. A method for driving a multi-port memory device, comprising the
steps of: entering a self-refresh mode in response to an
inactivation of a test-flag signal applied in a test mode; and
escaping from the self-refresh mode in response to an activation of
the test-flag signal, wherein the entering step includes:
generating an entry signal in response to the inactivation of the
test-flag signal; activating an interval signal during the
activation of the entry signal; activating a cycle-pulse signal at
regular cycle intervals during the activation of the interval
signal; generating a new internal refresh signal for self-refresh
execution in response to the activation of the entry signal and the
cycle-pulse signal; and increasing a row address by one bit
whenever the internal refresh signal is activated to thereby output
an internal address.
16. The method as recited in claim 15, wherein the test-flag signal
is applied from outside through a pad.
17. The method as recited in claim 15, wherein the test-flag signal
is generated by a combination of a plurality of test codes.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to semiconductor design
technologies, and more particularly, to a multi-port memory device
capable of performing a self-refresh operation by only a single
flag signal or test signal.
DESCRIPTION OF RELATED ART
[0002] Generally, data is stored in cell capacitors in a charge
form in Dynamic Random Access Memory (DRAM), but such charge may be
lost due to a leakage current and the like. Therefore, it is
required to conduct repeated processes of reading and amplifying
the stored data and again writing it in regular cycles before the
data becomes completely lost. This is called a refresh
operation.
[0003] A refresh is generally classified into an auto-refresh and a
self-refresh. The auto-refresh implies a refresh that is carried
out by taking an auto-refresh command from outside every certain
time. The self-refresh is an operation mode devised to reduce power
consumption among lots of operation modes of a semiconductor memory
device, wherein only a self-refresh entry command is provided from
an external chip set to the memory device without giving any other
commands thereto. Thereafter, the semiconductor memory device
itself conducts the refresh operation by an inner timer until
receipt of a self-refresh escape command. During the self-refresh
mode, devices such as an input buffer and a delay-lock loop which
are not related to the self-refresh are turned off in order to
minimize power consumption.
[0004] FIG. 1 shows a block diagram of a conventional semiconductor
memory device with a self-refresh mode.
[0005] Referring to FIG. 1, the conventional semiconductor memory
device includes a mode input/output controller 10 for receiving a
clock enable signal CKE and an auto-refresh command AR (or
AREF_CMD) and generating an internal auto-refresh signal AREFP, a
self-refresh entry signal SREF_EN and a self-refresh escape signal
SREF_EXP, a refresh interval signal generator 20 for taking the
internal auto-refresh signal AREFP, the self-refresh entry signal
SREF_EN and the self-refresh escape signal SREF_EXP and producing a
self-refresh interval signal SREF notifying a self-refresh
interval, a refresh cycle signal generator 30 for periodically
providing a cycle-pulse signal PL_FLG during an activation of the
self-refresh interval signal SREF, an internal refresh signal
generator 40 for activating an internal address REFP in response to
the internal auto-refresh signal AREFP and the cycle-pulse signal
PL_FLG, and an internal address counter 50 for increasing a row
address by bit units in response to the internal refresh signal
REFP to provide an internal address RCNTI[0:N].
[0006] For reference, the clock enable signal CKE is a signal
indicating whether a clock to synchronize an operation of the
semiconductor memory device is valid or not. Therefore, when only
the clock enable signal is inactivated, the semiconductor memory
device enters a power down mode to minimize its own power
consumption.
[0007] FIG. 2 is an internal circuit diagram of the refresh
interval signal generator 20 shown in FIG. 1.
[0008] Referring to FIG. 2, the refresh interval signal generator
20 is provided with a signal generator 22 for activating an output
signal when the self-refresh entry signal SREF_EN and the internal
auto-refresh signal AREFP are activated and inactivating it when
the self-refresh escape signal SREF_EXP is activated, a latch 24
for latching the output signal of the signal generator 22, and an
inverter I1 for inverting the output signal of the signal generator
22 to provide the self-refresh interval signal SREF.
[0009] The following is a brief operation explanation of the
refresh interval signal generator 20.
[0010] First of all, when the self-refresh entry signal SREF_EN and
the internal auto-refresh signal AREFP are all activated to a logic
high level, the signal generator 22 activates an output signal to a
logic low level. Then, the latch 24 latches the output signal of
the signal generator 22 and the inverter I1 inverts the same to
activate the self-refresh interval signal SREF to a logic high
level.
[0011] In the meantime, when the self-refresh escape SREF_EXP is
activated to a logic low level, the signal generator 22 inactivates
an output signal to a logic high level. Then, the latch 24 latches
the output signal of the signal generator 22 and the inverter I1
inverts it to inactivate the self-refresh interval signal SREF.
[0012] In other words, when the self-refresh entry signal SREF_EN
and the internal auto-refresh signal AREFP are activated, the
refresh interval signal generator 20 activates the self-refresh
interval signal SREF and keeps the activation state until the
self-refresh escape signal SREF_EXP is applied thereto. After that,
when the self-refresh escape signal SREF_EXP is inputted, the
refresh interval signal generator 20 inactivates the self-refresh
interval signal SREF.
[0013] FIG. 3 offers an operation waveform of the semiconductor
memory device with the self-refresh mode, as shown in FIGS. 1 and
2. An operation of the self-refresh mode will be explained below in
detail with reference to FIG. 3.
[0014] As shown in FIG. 3, the clock enable signal CKE is first
transited to a logic low level, and also, the auto-refresh command
AR is activated.
[0015] Then, in response to the logic low level transition of the
clock enable signal CKE, the mode input/output controller 10
activates the self-refresh entry signal SREF_EN, and in response to
the auto-refresh command AR, it activates the internal auto-refresh
signal AREFP.
[0016] Subsequently, the internal refresh signal generator 40
generates the internal refresh signal REFP in response to the
internal auto-refresh signal AREFP.
[0017] And then, the internal address counter 50 increases a row
address by one bit whenever the internal refresh signal REFP is
activated, to thereby output the internal address RCNTI[0:N].
[0018] In response to the activation of the internal auto-refresh
signal AREFP and the self-refresh entry signal SREF_EN, the
self-refresh interval signal generator 20 activates the
self-refresh interval signal SREF and maintains such state until
the self-refresh escape signal SREF_EXP is applied thereto.
[0019] Thereafter, the refresh cycle signal generator 30
periodically activates the cycle-pulse signal PL_FLG during the
activation of the self-refresh interval signal SREF.
[0020] In succession, the interval refresh signal generator 40
activates a new internal refresh signal REFP of pulse shape
whenever the cycle-pulse signal PL_FLG is inputted thereto.
[0021] Then, the internal address counter 50 increases a row
address by one bit whenever the internal refresh signal REFP is
activated, to thereby provide the internal address RCNTI[0:N].
[0022] For reference, the internal refresh signal REFP is applied
to each bank so that a word line corresponding to the internal
address RCNTI[0:N] is active and thus the self-refresh is
performed.
[0023] As described above, the conventional semiconductor memory
device enters the self-refresh mode to perform such mode when the
clock enable signal CKE inactivated to a logic low level is applied
thereto together with the auto-refresh command AR, and thereafter,
ends the execution of the self-refresh mode when the clock enable
signal CKE is activated to a logic high level.
[0024] Namely, the conventional semiconductor memory device enters
the self-refresh mode when the clock enable signal is applied
thereto, together with the auto-refresh command. This is to
distinguish from a case of entering the power down mode when only
the clock enable signal is inactivated.
[0025] In this regard, the applicant of the present invention filed
a multi-port memory device which is assigned Korean Patent
Application No. 10-2006-32948.
[0026] However, this multi-port memory device does not perform the
power down mode and the self-refresh mode separately, and
therefore, there has been a need of a new self-refresh driving
method.
SUMMARY OF THE INVENTION
[0027] It is, therefore, an object of the present invention to
provide a multi-port memory device capable of performing a
self-refresh operation in response to a single flag signal or test
signal.
[0028] In accordance with the present invention, there is provided
a multi-port memory device including: a mode input/output
controller for receiving a flag signal and generating a
self-refresh entry signal and a self-refresh escape signal; a
refresh interval signal generator for providing a self-refresh
interval signal notifying a self-refresh interval in response to
the self-refresh entry signal and the self-refresh escape signal; a
refresh cycle signal generator for periodically generating a
cycle-pulse signal during an activation of the self-refresh
interval signal; an internal refresh signal generator for producing
an internal refresh signal in response to the self-refresh entry
signal and the cycle-pulse signal; and an internal address counter
for generating an internal address in response to the internal
refresh signal.
[0029] The other objectives and advantages of the invention will be
understood by the following description and will also be
appreciated by the embodiments of the invention more clearly.
Further, the objectives and advantages of the invention will
readily be seen that they can be realized by the means and its
combination specified in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The above and other objects and features of the instant
invention will become apparent from the following description of
preferred embodiments taken in conjunction with the accompanying
drawings, in which:
[0031] FIG. 1 shows a block diagram of a conventional semiconductor
memory device having a self-refresh mode;
[0032] FIG. 2 is an internal circuit diagram of the refresh
interval signal generator shown in FIG. 1;
[0033] FIG. 3 offers an operational waveform of the semiconductor
memory device with the self-refresh mode shown in FIGS. 1 and
2;
[0034] FIG. 4 is a block diagram showing a configuration of a
multi-port memory device having a self-refresh mode in accordance
with a first embodiment of the present invention;
[0035] FIG. 5 illustrates an internal circuit diagram of the mode
input/output controller shown in FIG. 4;
[0036] FIG. 6 illustrates an internal circuit diagram of the
refresh interval signal generator shown in FIG. 4;
[0037] FIG. 7 provides an operational waveform that simply shows a
procedure for the multi-port memory device of the present invention
to enter a self-refresh mode and escape therefrom;
[0038] FIG. 8 illustrates an internal circuit diagram of the mode
input/output controller of FIG. 4, to which an initialization
signal is applied;
[0039] FIG. 9 illustrates a block diagram of a multi-port memory
device having a self-refresh test mode in accordance with a second
embodiment of the present invention;
[0040] FIG. 10 illustrates an internal circuit diagram of the
test-clock enable signal generator shown in FIG. 9;
[0041] FIG. 11 is a circuit diagram exemplifying another embodiment
of the test-clock enable signal generator shown in FIG. 9;
[0042] FIG. 12 illustrates an internal circuit diagram of the mode
input/output controller shown in FIG. 9; and
[0043] FIG. 13 offers an internal circuit diagram in accordance
with another embodiment of the mode input/output controller shown
in FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
[0044] Hereinafter, preferred embodiments of the present invention
will be set forth in detail with reference to the accompanying
drawings so that the invention can be readily carried out by those
in the art to which the invention pertains.
[0045] FIG. 4 is a block diagram showing a configuration of a
self-refresh apparatus for a multi-port memory device in accordance
with a first embodiment of the present invention.
[0046] Referring to FIG. 4, the self-refresh apparatus in
accordance with the first embodiment of the present invention
includes a mode input/output controller 100 for receiving a clock
enable signal CKE and generating a self-refresh entry signal
SREF_EN and a self-refresh escape signal SREF_EXP, a refresh
interval signal generator 200 for producing a self-refresh interval
signal SREF notifying a self-refresh interval in response to the
self-refresh entry signal SREF_EN and the self-refresh escape
signal SREF_EXP, a refresh cycle signal generator 300 for
periodically providing a cycle-pulse signal PL_FLG during an
activation of the self-refresh interval signal SREF, an internal
refresh signal generator 400 for generating an internal address
REFP in response to the self-refresh entry signal SREF_EN and the
cycle-pulse signal PL_FLG, and an internal address counter 500 for
producing an internal address RCNTI[0:N] in response to the
internal refresh signal REFP.
[0047] In comparison with the conventional device shown in FIG. 1,
it can be seen that the self-refresh apparatus for the multi-port
memory device of the present invention allows the mode input/output
controller 100 that senses an entry into a self-refresh mode to
take only the clock enable signal CKE in order to generate only the
self-refresh entry signal SREF_EN and the self-refresh escape
signal SREF_EXP, and also the refresh interval signal generator 200
to receive only the self-refresh entry signal SREF_EN and the
self-refresh escape signal SREF_EXP.
[0048] In other words, it can be known that the self-refresh
apparatus according to the first embodiment of the present
invention accepts only the clock enable signal CKE and enters the
self-refresh mode or escapes therefrom, thereby enabling a simpler
circuit implementation.
[0049] As can be seen from the above, other blocks except for the
mode input/output controller 100 and the refresh interval signal
generator 200 are the same as those of the conventional device.
Accordingly, the mode input/output controller 100 and the refresh
interval signal generator 200 will be described below in detail
with reference to their detailed circuit diagrams.
[0050] FIG. 5 illustrates an internal circuit diagram of the mode
input/output controller 100 of FIG. 4, designated by reference
numeral 100A.
[0051] Referring to FIG. 5, the mode input/output controller 100A
is provided with a self-refresh entry signal generator 120 for
sensing an inactivation of the clock enable signal CKE to generate
the self-refresh entry signal SREF_EN, and a self-refresh escape
signal generator 140 for sensing an activation of the clock enable
signal CKE to produce the self-refresh escape signal SREF_EXP.
[0052] More specifically, the self-refresh entry signal generator
120 is composed of an RS latch 122 for taking the clock enable
signal CKE as a set signal and a feedback signal as a reset signal,
an inversion delay circuit 124 for delaying and inverting a
positive output of the RS latch 122 to output the feedback signal,
a NAND gate ND1 for taking and NAND-operating the positive output
and the feedback signal, an inverter 12 for inverting an output
signal of the NAND gate ND1 to generate the self-refresh entry
signal SREF_EN.
[0053] In the meantime, the self-refresh escape signal generator
140 is composed of an inverter 13 for inverting the clock enable
signal CKE, an RS latch 142 for taking an output signal of the
inverter 13 as a set signal and a feedback signal as a reset
signal, an inversion delay circuit 144 for delaying and inverting a
positive output of the RS latch 142 to output the feedback signal,
a NAND gate ND2 for accepting and NAND-operating the positive
output and the feedback signal, a delay circuit 146 for delaying an
output signal of the NAND gate ND2 to create the self-refresh
escape signal SREF_EXP.
[0054] The following is a brief operation description of the mode
input/output controller 100A.
[0055] First of all, the clock enable signal CKE is inactivated to
a logic low level.
[0056] Next, in response to the inactivation of the clock enable
signal CKE, the RS latch 122 in the self-refresh entry signal
generator 120 activates the self-refresh entry signal SREF_EN to a
logic high level, and after a delay time by the inversion delay
circuit 144, the feedback signal becomes a logic low level and thus
the self-refresh entry signal SREF_EN becomes inactivated.
[0057] And then, when the clock enable signal CKE is activated to a
logic high level, the RS latch 142 in the self-refresh escape
signal generator 140 activates the self-refresh escape signal
SREF_EXP to a logic low level, and after a delay time by the
inversion delay circuit 144, inactivates it to a logic high
level.
[0058] That is, when the clock enable signal CKE is transited from
a logic high level to a logic low level, the mode input/output
controller 101A senses such transition and triggers the
self-refresh entry signal SREF_EN of pulse shape to be in a high
active state. And when the clock enable signal CKE is again
activated to a logic high level, it senses such state and causes
the self-refresh escape signal SREF_EXP of pulse shape to be in a
low active state.
[0059] Therefore, the self-refresh apparatus having the mode
input/output controller 100A as mentioned above enters the
self-refresh mode or escapes therefrom by sensing only a change of
logic level of the clock enable signal CKE.
[0060] FIG. 6 exemplifies an internal circuit diagram of the
refresh interval signal generator 200 shown in FIG. 4.
[0061] Referring to FIG. 6, the refresh interval signal generator
200 is provided with a signal generator 220 for activating an
output signal in response to the self-refresh entry signal SREF_EN
and inactivating it in response to the self-refresh escape signal
SREF_EXP, a latch 240 for latching an output signal of the signal
generator 220, and an inverter 14 for inverting the output signal
of the signal generator 240 to generate the self-refresh interval
signal SREF.
[0062] The signal generator 220 is composed of a PMOS transistor
PM1 for taking the self-refresh escape signal SREF_EXP via its gate
and having a source-drain path between an external voltage VDD and
an output node N1, and an NMOS transistor NM1 for accepting the
self-refresh entry signal SREF_EN via its gate and having a
drain-source path between the output node N1 and a ground voltage
VSS, wherein a voltage on the output node N1 is provided as an
output signal.
[0063] The following is a brief operation explanation of the
refresh interval signal generator 200.
[0064] First of all, when the self-refresh signal SREF_EN is
activated to a logic high level, the signal generator 220 activates
an output signal to a logic low level and keeps the state until the
self-refresh escape signal SREF_EXP is applied thereto. Then, the
latch 240 latches the output signal of the signal generator 220 and
the inverter 14 inverts the output signal to provide the
self-refresh interval signal SREF activated to a logic high
level.
[0065] Meanwhile, when the self-refresh escape signal SREF_EXP is
activated to a logic low level, the signal generator 220
inactivates an output signal and keeps the state until the
self-refresh entry signal SREF_EN is applied thereto. Then, the
latch 240 latches an output signal of the signal generator 220 and
the inverter 14 inverts the output signal to inactivate the
self-refresh interval signal SREF.
[0066] That is, the refresh interval signal generator 200 activates
the self-refresh interval signal SREF in response to the activation
of the self-refresh entry signal SREF_EN, and inactivates it when
the self-refresh escape signal SREF_EXP is applied. Thus, the
self-refresh interval signal SREF is continuously activated to a
logic high level during the self-refresh mode, to thereby notify
that the current mode is in the self-refresh mode.
[0067] Hereinafter, a brief operation description of the
self-refresh apparatus shown in FIGS. 4 to 6 will be given.
[0068] First of all, when the clock enable signal CKE is
inactivated at a logic low level, the mode input/output controller
100 activates the self-refresh entry signal SREF_EN, and then, the
refresh interval signal generator 200 activates the self-refresh
interval signal SREF. Thereafter, the refresh cycle signal
generator 300 activates the cycle-pulse signal PL_FLG of pulse
shape at regular cycle intervals during the activation of the
self-refresh interval signal SREF. In succession, the interval
refresh signal generator 400 creates the internal refresh signal
REFP in response to the self-refresh entry signal SREF_EN, and
creates the new internal refresh signal REFP of pulse shape
whenever the cycle-pulse signal PL_FLG is activated. Then, the
internal address counter 500 increases a row address by one bit
whenever the internal refresh signal REFP is activated, to thereby
output the internal address RCNTI[0:N].
[0069] Meanwhile, when the clock enable signal CKE is activated to
a logic high level, the mode input/output controller 100 activates
the self-refresh escape signal SREF_EXP, and thus, inactivates the
self-refresh interval signal SREF. Accordingly, the refresh cycle
signal generator 300 is turned off in response to the inactivation
of the self-refresh interval signal SREF. In succession, the
interval refresh signal generator 400 creates no internal refresh
signal REFP because the cycle-pulse signal PL_FLG is not applied
thereto. Then, the internal address counter 500 is turned off
because the internal refresh signal REFP is also applied
thereto.
[0070] For reference, although not shown in the figure, the
internal refresh signal REFP is applied to each bank to activate a
word line corresponding to an internal address RCNTI[0:N], so that
the self-refresh is carried out.
[0071] The procedure for the self-refresh apparatus of the present
invention to enter the self-refresh mode or escape therefrom as set
forth above will be roughly illustrated below referring to FIG.
7.
[0072] Referring to FIG. 7, the self-refresh apparatus for the
multi-port memory device in accordance with the present invention
enters the self-refresh mode when the clock enable signal CKE is at
a logic low level, and escapes therefrom when the clock enable
signal CKE is activated to a logic high level.
[0073] Namely, it can be seen that the present invention enters the
self-refresh mode using only the clock enable signal CKE, while the
conventional device enters the self-refresh mode by sensing receipt
of the auto-refresh command AR together with the clock enable
signal CKE.
[0074] Therefore, the self-refresh apparatus in accordance with the
present invention can be implemented by a simpler circuit
configuration compared to the conventional device. Also, the
present invention does not require that the input buffer for taking
the auto-refresh command AR be always active.
[0075] Meanwhile, by applying an initialization signal RST to the
mode input/output controller 100, it is possible for the
self-refresh entry signal SREF_EN and the self-refresh escape
signal SREF_EXP to have certain levels, without any error, upon an
initial operation. Details thereof will be provided below referring
to the figure.
[0076] FIG. 8 exemplifies an internal circuit diagram of the mode
input/output controller 100 of FIG. 4, indicated by reference
numeral 100B, to which an initialization signal RST is applied.
[0077] Referring to FIG. 8, the mode input/output controller 100B
that is stable upon an initial operation is composed of a
self-refresh entry signal generator 160 for generating the
self-refresh entry signal SREF_EN by sensing an inactivation of the
clock enable signal CKE and initializing the signal SREF_EN upon
receipt of the initialization signal PST, and a self-refresh escape
signal generator 180 for producing the self-refresh escape signal
SREF_EXP by sensing an activation of the clock enable signal CKE
and initializing the signal SREF_EXP upon receipt of the
initialization signal RST.
[0078] In comparison with the mode input/output controller 100B
shown in FIG. 8 and that in FIG. 5, they have the same circuit
configuration, but are different from each other in that the
initialization signal RST is applied to each RS latch in the
self-refresh entry signal generator 160 and the self-refresh escape
signal generator 180 as a reset signal. Accordingly, when the
initialization signal RST as the reset signal is activated to a
logic low level, the self-refresh entry signal generator 160 and
the self-refresh escape signal generator 180 are designed in such a
way that the self-refresh entry signal SREF_EN has a logic low
level and the self-refresh escape signal SREF_EXP has a logic high
level.
[0079] Besides, an operation associated with the level 2,
transition of the clock enable signal CKE is made in the same
manner as the conventional device, and thus, its detailed
description will be omitted here for brevity.
[0080] As mentioned above, the mode input/output controller 100B
according to another embodiment of the present invention as shown
in FIG. 8 further receives the initialization signal RST, and thus
permits the self-refresh entry signal SREF_EN and the self-refresh
escape signal SREF_EXP to have more stable levels during the
initial operation.
[0081] Meanwhile, the following is a detailed description of the
self-refresh apparatus that allows an entry into the self-refresh
mode from a test mode.
[0082] FIG. 9 exemplifies a block diagram of a self-refresh
apparatus having a test mode for a multi-port memory device in
accordance with a second embodiment of the present invention.
[0083] Referring to FIG. 9, the self-refresh apparatus in
accordance with the second embodiment of the present invention
includes a test-clock enable signal generator 600 for providing a
test-clock enable signal CKE_TST, a mode input/output controller
700 for receiving a clock enable signal CKE or the test-clock
enable signal CKE_TST in response to a test signal TST_EN and
generating a self-refresh entry signal SREF_EN and a self-refresh
escape signal SREF_EXP, a refresh interval signal generator 200 for
providing a self-refresh interval signal SREF notifying a
self-refresh interval in response to the self-refresh entry signal
SREF_EN and the self-refresh escape signal SREF_EXP, a refresh
cycle signal generator 300 for periodically generating a
cycle-pulse signal PL_FLG during an activation of the self-refresh
interval signal SREF, an internal refresh signal generator 400 for
producing an internal refresh signal REFP in response to the
self-refresh entry signal SREF_EN and the cycle-pulse signal
PL_FLG, and an internal address counter 500 for generating an
internal address RCNTI[0:N] in response to the internal refresh
signal REFP.
[0084] When compared with the first embodiment of the present
invention shown in FIG. 4, the self-refresh apparatus of the second
embodiment of the present invention further includes the test-clock
enable signal generator 600 to thereby generate the test-clock
enable signal CKE_TST. In addition, it can be seen that the
self-refresh apparatus enters the self-refresh mode or escapes
therefrom in response to the test-clock enable signal CKE_TST upon
the test mode by applying the test signal TST_EN to the mode
input/output controller 700. Accordingly, although the clock enable
signal CKE is not applied upon the test, it is possible to test the
self-refresh operation regardless of such state.
[0085] Further, upon a normal operation, the self-refresh apparatus
has the same configuration as that of the first embodiment of the
present invention which enters the self-refresh mode to perform the
self-refresh by receiving the clock enable signal CKE from the
outside. Therefore, in the following description, only the
test-clock enable signal generator 600 and the mode input/output
controller 700 will be discussed in detail.
[0086] FIG. 10 illustrates an internal circuit diagram of the
test-clock enable signal generator 600 shown in FIG. 9, given as
reference numeral 600A.
[0087] As shown therein, the test-clock enable signal generator
600A is a pad 620 that can accept the test-clock enable signal
CKE_TST directly from the outside during the test.
[0088] FIG. 11 exemplifies a circuit diagram of another embodiment
of the test-clock enable signal generator 600 shown in FIG. 9,
designated by reference numeral 600B.
[0089] Referring to FIG. 11, the test-clock enable signal generator
600B is composed of a decoder 640 for decoding test codes TST_CD1
and TST_CD2, a flag generator 660 for creating an output signal in
response to output signals of the decoder 640, a latch 680 for
inverting and latching the output signal of the flag generator 660,
and a delay circuit 690 for delaying an output signal of the latch
680 to provide the test-clock enable signal CKE_TST.
[0090] As such, the test-clock enable signal generator 600B shown
in FIG. 11 decodes the test codes TST_CD1 and TST_CD2 to produce
the test-clock enable signal CKE_TST. In other words, it can
produce the test-clock enable signal CKE_TST through a combination
of the test codes TST_CD1 and TST_CD2.
[0091] For reference, the output signals test1 and test2 of the
decoder 640 may be employed for other operations during the test
mode.
[0092] FIG. 12 exemplifies an internal circuit diagram of the mode
input/output controller 700 of FIG. 9, indicated by reference
numeral 700A.
[0093] Referring to FIG. 12, the mode input/output controller 700A
is provided with a selector 710 for selectively providing the clock
enable signal CKE or the test-clock enable signal CKE_TST in
response to the test signal TST_EN, a self-refresh entry signal
generator 720 for generating the self-refresh entry signal SREF_EN
in response to an output signal of the selector 710, and a
self-refresh escape signal generator 730 for providing the
self-refresh escape signal SREF_EXP in response to the output
signal of the selector 710.
[0094] When compared with the mode input/output controller 100A
shown in FIG. 5, it can be seen that the mode input/output
controller 700A of FIG. 12 further includes only the selector 710,
and other blocks have the same configuration. Thus, only the
selector 710 will be described in detail below.
[0095] The selector 710 is composed of a transfer gate TG1 for
transferring the clock enable signal CKE to the self-refresh entry
signal generator 720 in response to an inactivation of the test
signal TST_EN, a transfer gate TG3 for transferring the clock
enable signal CKE to the self-refresh escape signal generator 730
in response to the inactivation of the test signal TST_EN, a
transfer gate TG2 for providing the test-clock enable signal
CKE_TST to the self-refresh entry signal generator 720 in response
to an activation of the test signal TST_EN, and a transfer gate TG4
for producing the test-clock enable signal CKE_TST to the
self-refresh escape signal generator 730 in response to the
activation of the test signal TST_EN.
[0096] Briefly explaining an operation, when the test signal TST_EN
is inactivated, the selector 710 in which the transfer gates TG1
and TG3 become active applies the clock enable signal CKE to each
of the self-refresh entry signal generator 720 and the self-refresh
escape signal generator 730. Then, the self-refresh entry signal
generator 720 activates the self-refresh entry signal SREF_EN when
the clock enable signal CKE is transited to a logic low level, and
the self-refresh escape signal generator 730 activates the
self-refresh escape signal SREF_EXP when the clock enable signal
CKE is transited to a logic high level.
[0097] Meanwhile, when the test signal TST_EN is activated, the
selector 710 in which the transfer gates TG2 and TG4 become active
applies the test-clock enable signal CKE_TST to each of the
self-refresh entry signal generator 720 and the self-refresh escape
signal generator 730. Then, the self-refresh entry signal generator
720 activates the self-refresh entry signal SREF_EN when the
test-clock enable signal CKE_TST is transited to a logic low level,
and the self-refresh escape signal generator 730 activates the
self-refresh escape signal SREF_EXP when the test-clock enable
signal CKE_TST is transited to a logic high level.
[0098] As described above, the self-refresh apparatus for the
multi-port memory according to the second embodiment of the present
invention performs the self-refresh in response to the test-clock
enable signal CKE_TST that is received directly from the outside
through the pad 600A or created through a combination of the test
codes TST_CD1 and TST_CD2 in the test mode where the test signal
TST_EN is activated. Namely, in the test mode, it is possible to
test the self-refresh operation regardless of the on/off state of
the input buffer for receiving the clock enable signal CKE.
[0099] Further, in the normal mode where the test signal TST_EN is
inactivated, it can be seen that the normal self-refresh is
performed in response to the clock enable signal CKE.
[0100] In the meantime, it is possible to stabilize levels of the
self-refresh signal SREF_EN and the self-refresh escape signal
SREF_EXP by accepting the initialization signal RST upon the
initial operation. This will be described below in detail referring
to the figure.
[0101] FIG. 13 illustrates an internal circuit diagram according to
another embodiment of the mode input/output controller 700 shown in
FIG. 9, designated by reference numeral 700B.
[0102] In comparison with the mode input/output controller 700A
shown in FIG. 12, it can be found that the mode input/output
controller 700B shown in FIG. 13 has the same circuit configuration
but takes the initialization signal RST through the self-refresh
entry signal generator 740 and the self-refresh escape signal
generator 750.
[0103] Also, it can be known that the self-refresh entry signal
generator 740 and the self-refresh escape signal generator 750 have
the same circuit configuration as that shown in FIG. 6.
[0104] Accordingly, it can be seen that the mode input/output
controller 700B according to another embodiment of the present
invention, when the initialization signal RST is activated,
inactivates the self-refresh entry signal SREF_EN to a logic low
level and the self-refresh escape signal SREF_EXP to a logic high
level, regardless of level of the clock enable signal CKE or the
test-clock enable signal CKE_TST. Further, in the test mode, it is
driven in the same way as in FIG. 12, and thus, details thereof
will be omitted.
[0105] Therefore, the self-refresh apparatus having the test mode
according to the second embodiment of the present invention
illustrated in FIGS. 9 to 13 conducts the self-refresh in response
to the test-clock enable signal CKE_TST which is received directly
from the outside through the pad 600A or created through a
combination of the test codes TST_CD1 and TST_CD2, in the test mode
where the test signal TST_EN is activated. Namely, even in the test
mode, it is possible to not only test the self-refresh operation
but also test the same regardless of receipt or level change of the
clock enable signal CKE.
[0106] Meanwhile, the self-refresh apparatuses for the multi-port
memory device according to the first and the second embodiments of
the present invention can enter the self-refresh or escape
therefrom by only the clock enable signal CKE. Thus, the present
invention has a simpler circuit configuration than that of the
conventional device which should apply the clock enable signal CKE
and the auto-refresh command AR together. Furthermore, the present
invention can test the self-refresh operation even in the test
mode.
[0107] In the present invention as set forth above, even though
there is illustrated a case of entering the self-refresh mode in
response to the inactivation of the clock enable signal and
escaping therefrom in response to the activation thereof, it is not
limited to a specific logic level of the clock enable signal or its
substitution signal. For example, the present invention can enter
the self-refresh mode during the activation of the clock enable
signal and also escape therefrom during the inactivation
thereof.
[0108] Further, in the present invention as mentioned above,
although there is illustrated a case of entering the self-refresh
mode in response to the logic level of the clock enable signal, it
is merely one embodiment but not limited to such signal. For
instance, it can be implemented to enter the self-refresh mode and
escape therefrom in response to a single flag signal for an entry
into the self-refresh mode.
[0109] Furthermore, in the present invention as set forth above,
even though there is illustrated an example where the test-clock
enable signal is generated by using the test codes of 2-bit, it
should be noted that the aspect of the present invention is not
limited to the number of bits of the test codes.
[0110] Moreover, although the new self-refresh apparatus for the
multi-port memory device is illustrated in the present invention as
described above, it should be noted that this can also be applied
to the existing semiconductor memory devices.
[0111] As a result, the present invention can perform the
self-refresh by only a single flag signal and also can test whether
to perform such operation normally.
[0112] The present application contains subject matter relaxed to
Korean patent application Nos. 2005-90904 and 2006-49135 filed with
the Korean Intellectual Property Office on Sep. 29, 2005 and May
31, 2006, the entire contents of which are incorporated herein by
reference.
[0113] While the present invention has been described with respect
to the particular embodiments, it will be apparent to those skilled
in the art that various changes and modifications may be made
without departing from the spirit and scope of the invention as
defined in the following claims.
* * * * *